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| | Abstract | | Our previous study proposed a method that enables accurate measurement of ultrasonic attenuation using sweep signals under the assumptions that velocity dispersion can be ignored and the quality factor is not dependent on frequency. This method is independent of the effect of windowing while the windowing effect underestimates the attenuation results. However, our numerical experiments demonstrate that the proposed method is largely influenced by the existence of overlapping sweep events such as multiple reflections between the source and receiver transducer. Thus, the applicability of the proposed method is limited to highly attenuative media, in which overlapping events are much smaller than direct sweep signals, because these multiple reflected events are largely attenuated. Furthermore, the results of the numerical experiments conducted in the present study indicate that the presence of velocity dispersion causes attenuation to be underestimated, although the proposed method is not so sensitive to the presence of velocity dispersion. We also demonstrate the usefulness of observing compressed pulse waveforms with shorter duration from the cross-correlation of sweep waveforms than the case of pulse generation. |
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